US6870558B2 - Optical fixing unit, illuminance correcting method for the same, and thermal printer - Google Patents
Optical fixing unit, illuminance correcting method for the same, and thermal printer Download PDFInfo
- Publication number
- US6870558B2 US6870558B2 US10/350,133 US35013303A US6870558B2 US 6870558 B2 US6870558 B2 US 6870558B2 US 35013303 A US35013303 A US 35013303A US 6870558 B2 US6870558 B2 US 6870558B2
- Authority
- US
- United States
- Prior art keywords
- illuminance
- luminous
- integral
- element array
- fixing unit
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related, expires
Links
- 230000003287 optical effect Effects 0.000 title claims abstract description 33
- 238000000034 method Methods 0.000 title claims description 27
- 238000009826 distribution Methods 0.000 claims abstract description 29
- 238000004519 manufacturing process Methods 0.000 claims abstract description 8
- 239000000463 material Substances 0.000 claims description 13
- 230000000087 stabilizing effect Effects 0.000 claims description 13
- 238000010438 heat treatment Methods 0.000 claims description 7
- 239000011159 matrix material Substances 0.000 claims description 6
- 230000008859 change Effects 0.000 claims description 4
- 238000004040 coloring Methods 0.000 description 28
- 238000003491 array Methods 0.000 description 16
- 230000002950 deficient Effects 0.000 description 10
- QSHDDOUJBYECFT-UHFFFAOYSA-N mercury Chemical compound [Hg] QSHDDOUJBYECFT-UHFFFAOYSA-N 0.000 description 9
- 229910052753 mercury Inorganic materials 0.000 description 9
- 230000008569 process Effects 0.000 description 8
- 238000012937 correction Methods 0.000 description 6
- 238000012360 testing method Methods 0.000 description 6
- 238000009792 diffusion process Methods 0.000 description 5
- 239000003086 colorant Substances 0.000 description 4
- 230000001276 controlling effect Effects 0.000 description 4
- 238000005259 measurement Methods 0.000 description 4
- 230000008439 repair process Effects 0.000 description 3
- 230000008542 thermal sensitivity Effects 0.000 description 3
- 230000007423 decrease Effects 0.000 description 2
- 239000006185 dispersion Substances 0.000 description 2
- 238000012423 maintenance Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 230000002093 peripheral effect Effects 0.000 description 2
- 230000001133 acceleration Effects 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 230000002542 deteriorative effect Effects 0.000 description 1
- 238000003384 imaging method Methods 0.000 description 1
- 208000037805 labour Diseases 0.000 description 1
- 230000000737 periodic effect Effects 0.000 description 1
- 229920003023 plastic Polymers 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 229910000679 solder Inorganic materials 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- 238000009966 trimming Methods 0.000 description 1
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
- B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
- B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
- B41J2/315—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by selective application of heat to a heat sensitive printing or impression-transfer material
- B41J2/32—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by selective application of heat to a heat sensitive printing or impression-transfer material using thermal heads
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
- B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
- B41J2202/00—Embodiments of or processes related to ink-jet or thermal heads
- B41J2202/30—Embodiments of or processes related to thermal heads
- B41J2202/34—Thermal printer with pre-coating or post-processing
Definitions
- the present invention relates to an optical fixing unit including a luminous-element array, which is used as a light source to emit fixing rays toward a thermosensitive recording material and in which a large number of luminous elements are arranged in matrix.
- the present invention further relates to an illuminance correcting method for the optical fixing unit and relates to a thermal printer using the optical fixing unit.
- thermosensitive recording paper in which at least three thermosensitive coloring layers coloring in different colors are stacked. Thermal sensitivity of the coloring layer is lower as a position thereof is lower.
- the first and second thermosensitive coloring layers which are respectively the uppermost layer and the adjacent layer thereof, possess fixation properties caused by ultraviolet rays of specific wavelength ranges.
- a thermal head disposed in a scanning direction is pressed thereon to perform thermal recording for the respective coloring layers.
- the ultraviolet rays are applied by using a fixing unit to fix the thermally-recorded coloring layer so that the upper coloring layer is prevented from coloring when the thermal recording is performed for the lower coloring layer.
- a mercury fluorescent lamp having a tube shape.
- a section of the mercury fluorescent lamp is generally circle so that the ultraviolet rays are uniformly radiated around the mercury fluorescent lamp.
- a reflector is disposed near the mercury fluorescent lamp in order to reflect the ultraviolet rays, which are uselessly radiated, toward the color thermosensitive recording paper.
- the mercury fluorescent lamp to be used has a double length of a width of the thermal recording paper (relative to the scanning direction) in consideration of light-amount attenuation caused at both ends of the mercury fluorescent lamp.
- the mercury fluorescent lamp has a disadvantage regarding arrangement space so that it is difficult to downsize the printer.
- the fixing unit When the fixing unit has a large size, a conveyance distance of the color thermosensitive recording paper becomes long and printing time increases. Since the mercury fluorescent lamp greatly depends on a temperature of a light amount, a control circuit is necessary for controlling the light amount in accordance with variations of the temperature. Further, since the light amount changes with the passage of time, periodic maintenance is required. As stated above, there are problems concerning the manufacture cost and the maintenance.
- the luminous-element array includes a large number of small luminous elements, which are arranged in a scanning direction and a feeding direction so as to form a matrix.
- the luminous element is a light emitting diode, for example.
- the luminous-element array uses many luminous elements.
- illuminance of the respective luminous elements vary.
- illuminance distribution becomes uneven in the scanning direction due to a mounting error of the luminous element.
- a primary object of the present invention is to easily correct illuminance dispersion of an optical fixing unit, which uses a luminous-element array, in a scanning direction.
- a second object of the present invention is to obtain an appropriate amount of fixing rays even if illuminance of a luminous-element array is changed due to variations of temperature.
- an illuminance correcting method for the optical fixing unit examines illuminance distribution in a scanning direction.
- the optical fixing unit is used in a thermal printer thermally recording an image by heating a thermosensitive recording material, which is conveyed in a feeding direction, with a thermal head disposed in the scanning direction.
- the optical fixing unit comprises a luminous-element array, as a light source, in which a large number of luminous elements radiating ultraviolet rays are arranged in matrix relative to the scanning direction and the feeding direction.
- the fixing unit performs optical fixation with the ultraviolet rays radiated from the light source, conveying the thermal recording material on which an image has been thermally recorded.
- integral illuminance of the luminous elements is obtained with respect to each of feeding-direction lines of the luminous-element array to examine the illuminance distribution in the scanning direction.
- the integral illuminance is corrected every line so as to even the illuminance distribution in the scanning direction.
- the luminous elements of the feeding-direction line of the luminous-element array are connected in series, and the integral illuminance thereof is corrected by adjusting electrical energy to be supplied to the luminous elements of each line.
- the measurement member measures illuminance of the luminous-element array.
- the control member compares a measured value of the measurement member with a desired value, which is set in advance, to control an amount of the rays to be received by the thermosensitive recording material.
- the control member for controlling the amount of the rays corrects the illuminance of the luminous-element array by changing a duty ratio of the drive-pulse signal.
- illuminance dispersion of the optical fixing unit may be easily corrected in the scanning direction. Further, an appropriate amount of the fixing rays may be obtained even if the illuminance of the luminous-element array is changed due to variations of temperature.
- FIG. 1 is a schematic illustration showing a structure of a color thermal printer
- FIGS. 2A and 2B are explanatory illustrations showing LED-arrangement of a luminous-element array and illuminance distribution thereof in a scanning direction;
- FIG. 3 is an explanatory illustration showing the illuminance distribution of the luminous-element array in the scanning direction, which is obtained at the time of manufacture;
- FIG. 4 is an explanatory illustration showing a manner for connecting LEDs
- FIGS. 5A and 5B are explanatory illustrations showing a current stabilizing circuit
- FIG. 6 is an explanatory illustration showing a measurement device for measuring the illuminance distribution in the scanning direction
- FIG. 7 is a flowchart showing a sequence for correcting the illuminance
- FIG. 8 is an explanatory illustration showing a way for measuring the illuminance distribution in the scanning direction with a CCD
- FIG. 9 is a schematic illustration showing a structure of a thermal printer in which an amount of rays is controlled during fixation
- FIGS. 10A and 10B are explanatory illustrations of a luminous-element array used in the thermal printer shown in FIG. 9 ;
- FIG. 11 is a flowchart showing a sequence for controlling an amount of the rays on the basis of illuminance correction
- FIG. 12 is a flowchart showing a sequence for controlling the amount of the rays on the basis of adjustment of conveyance speed
- FIG. 13 is an explanatory illustration showing an example of the current stabilizing circuit in a case that temperature of a substrate is measured.
- a color thermal printer 2 shown in FIG. 1 reciprocates a color thermosensitive recording paper 3 in a forward direction and a backward direction to thermally record a full-color image and optically fix the color thermosensitive recording paper 3 on which the image is thermally recorded.
- the color thermal printer 2 comprises a thermal head 6 , a platen roller 7 , a conveyor roller pair 8 , an optical fixing unit 9 , and a controller 11 .
- the thermal head 6 heats and colors each of thermosensitive coloring layers of the recording paper 3 .
- the platen roller 7 confronts the thermal head 6 to support the recording paper 3 .
- the conveyor roller pair 8 conveys the recording paper 3 .
- the controller 11 controls each section of the printer.
- the color thermosensitive recording paper 3 comprises a cyan thermosensitive coloring layer, a magenta thermosensitive coloring layer, and a yellow thermosensitive coloring layer, which are stacked in order on a support as well known.
- the yellow thermosensitive coloring layer is the uppermost layer and has the highest thermal sensitivity so as to color in yellow with small thermal energy.
- the cyan thermosensitive coloring layer is the lowermost layer and has the lowest thermal sensitivity so as to color in cyan with great thermal energy.
- the yellow thermosensitive coloring layer which is the first thermosensitive coloring layer, loses an ability to color when near ultraviolet rays of 420 nm is applied thereto.
- the magenta thermosensitive coloring layer which is the second thermosensitive coloring layer, colors in magenta with thermal energy intermediately ranked between those of the yellow and cyan thermosensitive coloring layers.
- the magenta thermosensitive coloring layer loses an ability to color when ultraviolet rays of 365 nm is applied thereto.
- the color thermosensitive recording paper 3 may have a four-layer structure by providing a black thermosensitive
- the conveyor roller pair 8 nips the fed recording paper 3 to convey it in a feeding direction. During this conveyance, the color thermosensitive recording paper 3 passes the thermal head 6 and the optical fixing unit 9 to execute a printing process. After the printing process, the recording paper 3 is cut into a predetermined size by a cutter, which is not shown, and is discharged to the outside of the color thermal printer 2 . Incidentally, the conveyance roller pair 8 is driven by a drive motor 12 .
- the thermal head 6 includes a large number of heating elements aligned in a scanning direction. Each of the heating elements generates thermal energy in accordance with pixel density so as to thermally record an image of each color of yellow, magenta and cyan on the respective thermosensitive coloring layers.
- the thermal head 6 is driven by a head driving circuit 13 .
- the optical fixing unit 9 comprises a yellow luminous-element array 16 , a magenta luminous-element array 17 , and an array driving circuit 18 for driving the respective arrays.
- the yellow and magenta luminous-element arrays 16 and 17 are optical fixers respectively used for yellow and magenta.
- the arrays 16 and 17 are disposed at a downstream side of the thermal head 6 in a forward direction, and luminescent faces thereof confront a recording surface of the color thermosensitive recording paper 3 .
- the yellow luminous-element array 16 is a light source for fixing the yellow thermosensitive coloring layer by emitting the near ultraviolet rays whose luminescent peak is 420 nm.
- the magenta luminous-element array 17 is a light source for fixing the magenta thermosensitive coloring layer by emitting ultraviolet rays whose luminescent peak is 365 nm.
- FIG. 2A shows the yellow luminous-element array 16 viewed from the bottom thereof.
- the yellow luminous-element array 16 includes a base 21 on which a large number of yellow light-emitting diodes (hereinafter, simply called as Y-LED) 23 are arranged in a matrix-like form in both directions of the scanning direction and the feeding direction.
- the Y-LED 23 emits the near ultraviolet rays whose luminescent peak is 420 nm.
- the Y-LEDs 23 are arranged in a zigzag form. Illuminance of the Y-LED 23 is high at a central position thereof and is low at a peripheral portion thereof. Thus, the illuminance falls at an intermediate position of the adjacent Y-LEDs 23 . In view of this, the Y-LEDs 23 are arranged in the zigzag form so that portions (peripheral portions) of the Y-LEDs 23 having low illuminance are adapted to compensate each other.
- FIG. 2B is a graph showing distribution of integral illuminance relative to the scanning direction.
- the integral illuminance is a total value obtained from the illuminance of the plural Y-LEDs 23 belonging to each of lines L 1 to L 36 extending in the feeding direction.
- a solid line represents the integral illuminance of the odd line
- a broken line represents the integral illuminance of the even line. Since the luminous-element array comprises a large number of LEDs, the integral illuminance of the respective lines are varied if a defective element is caused by bad lighting of the LED, bad wiring and so forth. Consequently, unevenness of fixation occurs.
- the integral illuminance of the respective lines are corrected, so as not to vary, in an examination process at the time of manufacturing the luminous-element array, such as described later.
- the distribution of the illuminance is adapted to become a even state such as shown in FIG. 2 B. In virtue of this, the fixation unevenness caused by the defective element is prevented.
- the Y-LEDs 23 of the respective lines L 1 to L 36 extending in the feeding direction are connected in series.
- a current stabilizing circuit 31 is connected to each of the lines L 1 to L 36 to stabilize an electric current flowing in the Y-LEDs 23 of the respective lines L 1 to L 36 .
- the current stabilizing circuit 31 includes a plurality of resistors R 1 to R 5 connected in parallel.
- the resistors R 1 to R 5 are connected to switches SW 1 to SW 5 respectively in series.
- a combined-resistance value is varied by turning on and off the respective switches SW 1 to SW 5 to adjust electrical energy to be supplied to the Y-LEDs 23 of the respective lines L 1 to L 36 . In virtue of this adjustment, the integral illuminance of each line is corrected.
- the resistors R 1 to R 5 are connected in parallel so that the combined-resistance value R becomes smaller as a number of the connected resistors increases. In contrast, the combined-resistance value R becomes greater as the number of the connected resistors decreases.
- a voltage is constant, a value of the current to be supplied to the line is changed by varying the combined-resistance value.
- the combined-resistance value R is lowered in the examination process of the manufacturing stage by increasing a number of the resistors to be connected. In doing so, the current value increases so that the integral illuminance also increases. In contrast, with respect to the line having higher integral illuminance, the combined-resistance value R is increased by reducing the number of the resistors to be connected. In doing so, the current value lowers so that the integral illuminance also lowers. In this way, the electrical energy to be supplied is adjusted relative to each of the lines L 1 to L 36 . Thus, the illuminance distribution in the scanning direction is corrected so as to become an even state.
- the resistance values of the resistors R 1 through R 5 are respectively set to 1000 ⁇ , 6725 ⁇ , 5850 ⁇ , 5100 ⁇ , and 4440 ⁇ .
- ranks of the integral illuminance are predetermined as five steps of A-rank to E-rank, and the resistors to be connected is determined in accordance with the respective ranks.
- a parentage (%) of each rank is based on the reference integral illuminance, which is set to 100% when there is no defective element.
- the integral illuminance of the respective lines L 1 to L 36 vary.
- the measured integral illuminance of the respective lines L 1 to L 36 are allocated to the respective ranks for selecting the resistor to be connected.
- the resistor R 1 In the case of the A-rank, only the resistor R 1 is connected. Consequently, only the switch SW 1 is turned on and the other switches SW 2 to SW 5 are turned off.
- the resistor R 1 and the resistor R 2 are connected. In this case, the switches SW 1 and SW 2 are turned on and the other switches are turned off.
- similar adjustment are carried out.
- the way of connecting the resistors is described in the embodiment using the switches SW 1 to SW 5 .
- the switches SW 1 to SW 5 may be removed.
- all the resistors R 1 to R 5 may be connected at the time of manufacture (in an initial condition). In this case, connection of the non-selected resistor is cut with a laser cutter and so forth.
- all the resistors may be set to a non-connection state in the initial condition. In this case, the selected resistor is connected by a solder at the time of adjustment.
- the illuminance is corrected every line by the adjusting member, which adjusts the integral illuminance of the respective lines extending in the feeding direction.
- the adjusting member which adjusts the integral illuminance of the respective lines extending in the feeding direction.
- FIG. 6 shows a way for measuring the integral illuminance of the yellow luminous-element array 16 .
- a measuring device 41 comprises a light-receiving-element array 42 , an illuminance measuring circuit 43 , and an illuminance-distribution-data producing section 44 .
- the light-receiving-element array 42 extends in the scanning direction of the yellow luminous-element array 16 , and is attached so as to be movable in the feeding direction thereof.
- the array 42 receives the light emitted from the respective Y-LEDs 23 , moving in the feeding direction. Further, the array 42 transmits an electric signal to the illuminance measuring circuit 43 in accordance with an amount of the received light.
- the illuminance measuring circuit 43 converts the electric signal, which is received from the array 42 , into a digital signal.
- the converted digital signal is transmitted to the illuminance-distribution-data producing section 44 .
- This section 44 integrates the illuminance of the respective Y-LEDs 23 relative to each line extending in the feeding direction. Successively, the section 44 calculates the integral illuminance of each line. In this way, is obtained illuminance-distribution data in the scanning direction, such as shown in FIG. 3 .
- the foregoing description concerns the yellow luminous-element array.
- the magenta luminous-element array has a similar structure, and the integral illuminance thereof is similarly measured.
- a description concerning the magenta luminous-element array is abbreviated.
- the integral illuminance of the respective lines L 1 to L 6 are corrected so as to even up the illuminance distribution in the scanning direction.
- the measured value of the integral illuminance is assigned to any of the ranks shown in FIG. 5B to select the resistors in accordance with this rank.
- the selected resistors among the resistors R 1 to R 5 are connected by turning on and off the respective switches SW 1 to SW 5 . Owing to this, the integral illuminance of each line is corrected and the illuminance distribution is evened in the scanning direction.
- the luminous-element array is forwarded to an assembling process for a printer.
- the illuminance correction is carried out by turning on and off the switches SW 1 to SW 5 in each line.
- the illuminance is easily corrected in comparison with the conventional method in which all the defective elements are searched to exchange and rewire them.
- the above embodiment relates to the device employing the light-receiving-element array comprising many phototransistors.
- an imaging device of a CCD camera 51 for instance, shown in FIG. 8 .
- the CCD camera 51 transfers light-amount data of the yellow and magenta luminous-element arrays 16 and 17 to the illuminance-distribution-data producing section 44 , which calculates the integral illuminance of each line on the basis of the data sent from the CCD camera 51 .
- the method for obtaining the illuminance-distribution data in the scanning direction it is possible to adopt another method in which fixation unevenness is examined by actually applying the fixing light to a test paper (color thermosensitive recording paper) to perform a fixation test.
- the yellow luminous-element array is turned on first to apply the fixing light during a passage of the test paper. After that, a thermal head gives the test paper thermal energy for recording a solid image of yellow. At this time, the thermal head is corrected so as not to cause unevenness of heating performed thereby.
- the yellow colors on a portion lacking the fixation are calculated the integral illuminance of the respective lines in the feeding direction of the yellow luminous-element array so that the illuminance-distribution data in the scanning direction is obtained.
- similar processes are executed.
- the resistors connected in parallel are used. Besides this kind of the resistor, it is possible to use, for instance, a variable resistor and a film resistor whose resistance value is adjusted by laser trimming.
- the integral illuminance of each line is corrected by adjusting the electric energy to be supplied to the respective line.
- the integral illuminance of each line may be corrected by repairing the defective element, for example, by rewiring it or exchanging the defective LED. In this case, it is unnecessary to repair all the defective elements.
- the repairing operation is performed for only the lines, which have lower integral illuminance in comparison with the others.
- a number of the luminous elements to be turned on may be reduced relative to the line having higher illuminance in comparison with the others. It is sufficient to carry out the correction such that the illuminance distribution is evened in the scanning direction.
- the correcting operation is lightened in comparison with the conventional operation.
- the luminous-element array less depends on the temperature of the light amount in comparison with the mercury lamp.
- the light amount of the luminous-element array is not controlled during the fixation.
- the light amount is likely to change in accordance with the variations in temperature. In view of this, the light amount may be controlled during the fixation.
- FIG. 9 shows a thermal printer 61 in which a light amount is controlled by correcting the illuminance of the luminous-element array during fixation.
- a member which is identical with that of the above embodiment is denoted by the same reference numeral.
- Luminous-element arrays 62 and 63 which are used for yellow and magenta respectively, receive electric power from an LED power source 64 .
- Illuminance sensors 66 and 67 are disposed at positions confronting light-emitting surfaces of the respective luminous-element arrays 62 and 63 .
- Each of the illuminance sensors 66 and 67 outputs an illuminance signal (sensor voltage) in accordance with the measured illuminance of each of the luminous-element arrays 62 and 63 .
- the illuminance signal is amplified by an amplifier 68 and is outputted to an A-D converter 69 .
- the amplifier 68 has a characteristic (LPF characteristic) for making only low-frequency component pass through.
- LPF characteristic characteristic for making only low-frequency component pass through.
- an output voltage of the amplifier 68 is relative to a mean value of the illuminance (measured illuminance) of the respective luminous-element arrays 62 and 63 .
- the luminous-element arrays 62 and 63 are driven by drive pulses so that these arrays are intermittently turned on.
- the amplifier 68 Since the amplifier 68 has the LPF characteristic, it is possible to measure the mean illuminance of the respective luminous-element arrays 62 and 63 within a fixed period, instead of measuring the maximum illuminance during one-time lighting of the respective luminous-element arrays 62 and 63 . It is needless to say that the amplifier 68 need not possess the LPF characteristic.
- the mean illuminance of the respective luminous-element arrays 62 and 63 may be measured by a CPU 71 on the basis of the output of the amplifier 68 .
- the A-D converter 69 converts the inputted illuminance signal of analog into digital data which is outputted to the CPU 71 .
- This CPU 71 compares the inputted illuminance data (measured illuminance) with a desired value, which is stored in a LUT 72 in advance, to correct the illuminance of the respective luminous-element arrays 62 and 63 .
- the luminous-element arrays 62 and 63 are driven by a drive-pulse signal outputted from the CPU 71 .
- reference numeral 65 denotes a diffusion plate for diffusing the rays, which are emitted from the respective luminous-element arrays 62 and 63 toward the color thermosensitive recording paper 3 .
- the plural luminous elements are arranged, it is necessary to arrange the luminous elements at certain intervals for the purpose of preventing deterioration to be caused by self heating of the respective luminous elements. Due to this, although the respective lines are adjusted so as to even out the illuminance distribution in the scanning direction, it is impossible to perfectly even out the illuminance distribution.
- the diffusion plate 65 by providing the diffusion plate 65 , the light from the luminous-element array is diffused to reduce the unevenness of the illuminance distribution.
- the diffusion plate 65 is formed from a transparent plastic material, for instance.
- the guide-plate may be used as the diffusion plate instead of providing the guide-plate and the diffusion plate separately.
- the yellow luminous-element array 62 is provided with current stabilizing circuits 76 for the respective lines L 1 to L 36 extending in the feeding direction.
- the current stabilizing circuit 76 is connected to the yellow LEDs 23 in series.
- the current stabilizing circuit 76 is a current generator for passing the constant current without being affected by the other circuit elements.
- the current stabilizing circuit 76 comprises a variable resistor 77 and a transistor 78 .
- the variable resistor 77 is for adjusting a value of the current flowing in each line.
- the yellow luminous-element array 62 is regulated so as to even out the illuminance distribution in the scanning direction by adjusting resistance values of the respective variable resistors 77 .
- the transistor 78 is a switching member, which controls the current flowing in each of the lines L 1 to L 36 to turn on and off the yellow LEDs 23 thereof.
- the drive-pulse signal from the CPU 71 is inputted into a base of the transistor 78 .
- the transistor 78 is turned on so that the yellow LED 23 of each line emits the light.
- the signal level of the drive pulse is low, the yellow LED 23 is turned off.
- the CPU 71 corrects the illuminance of the yellow luminous-element array 62 during the fixation by changing a duty ratio of the drive-pulse signal in accordance with the illuminance signal.
- the duty ratio is a ratio of W to T shown in FIG. 10B , wherein T represents a cycle of a pulse train and W represents the duration of the pulse.
- the transistor 78 is provided for each line, the drive-pulse signals to be inputted into the respective transistors 78 are the same relative to all the line L 1 to L 36 .
- the transistor 78 By providing the transistor 78 for each line, it is possible to change the line to be turned on in accordance with a width of the color thermosensitive recording paper 3 .
- the yellow luminous-element array 62 is described as an example.
- the magenta luminous-element array 63 has a similar structure so that description thereof is abbreviated.
- FIG. 11 shows a flowchart of the illuminance correction to be executed during the fixation.
- the yellow luminous-element array 62 and the magenta luminous-element array 63 are respectively turned on.
- the illuminance sensors 66 and 67 output the illuminance signal (measured illuminance) to the amplifier 68 .
- the CPU 71 compares the measured illuminance with the desired value to change the duty ratio of the drive-pulse signal. In other words, when the measured illuminance is lower than the desired value, the duty ratio is increased to raise the illuminance. In contrast, when the measured illuminance is higher than the desired value, the duty ratio is reduced to lower the illuminance. This correction is carried out at fixed intervals until the fixation is completed.
- a light amount to be received by the color thermosensitive recording paper 3 may be corrected by adjusting a conveyance speed for conveying the recording paper 3 , such as shown by a flowchart in FIG. 12 .
- the illuminance is measured by the illuminance sensor, and the measured illuminance is compared with the desired value.
- the conveyance speed is slowed (retardation) to increase the light amount to be received.
- the conveyance speed is raised (acceleration) to reduce the light amount to be received.
- the allowable maximum current thereof changes in accordance with the temperature. This maximum current is smaller as the temperature is higher. If the current exceeding the maximum current flows in the luminous element, the life thereof is shortened. Thus, the current flowing in the luminous element is preferable to be prevented, in accordance with the temperature of the luminous element, from exceeding the maximum current value.
- a current stabilizing circuit 81 shown in FIG. 13 can measure the temperature of the base so that the temperature of the luminous element may be estimated from the temperature of the base. By using the current stabilizing circuit 81 , the current flowing therein may be controlled in accordance with the temperature of the luminous element so as to be the allowable maximum current value or less. Thus, the luminous-element array is prevented from deteriorating.
- the current stabilizing circuit 81 comprises the variable resistor 77 and two transistors 82 and 83 .
- a voltage of a terminal to which a drive-pulse signal is inputted from the CPU 71 is the sum of base-emitter voltages Vbe of the respective transistors 82 and 83 .
- the CPU 71 measures the voltage of the terminal to measure the temperature of the base. At the same time, the CPU 71 estimates the temperature of the luminous element from the measured temperature of the base.
- the CPU 71 adjusts the duty ratio of the drive pulse in accordance with the estimated temperature of the luminous element such that the current flowing in the luminous element is adjusted so as to be the maximum current value or less. In this case, the duty ratio must be lowered as the temperature becomes higher. Consequently, the illuminance of the luminous-element array declines. A decrease of the illuminance is compensated by adjusting a speed for conveying the color thermosensitive recording paper. A desired amount of the fixing light is secured by adjusting the conveying speed so that imperfect fixation is not caused.
Landscapes
- Electronic Switches (AREA)
Abstract
Description
Claims (29)
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2002-019048 | 2002-01-28 | ||
JP2002019048 | 2002-01-28 | ||
JP2002208675A JP2003285456A (en) | 2002-01-28 | 2002-07-17 | Optical fixing unit, its illuminance correcting method and thermal printer |
JP2002-208675 | 2002-07-17 |
Publications (2)
Publication Number | Publication Date |
---|---|
US20030142195A1 US20030142195A1 (en) | 2003-07-31 |
US6870558B2 true US6870558B2 (en) | 2005-03-22 |
Family
ID=27615711
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/350,133 Expired - Fee Related US6870558B2 (en) | 2002-01-28 | 2003-01-24 | Optical fixing unit, illuminance correcting method for the same, and thermal printer |
Country Status (2)
Country | Link |
---|---|
US (1) | US6870558B2 (en) |
JP (1) | JP2003285456A (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20050007439A1 (en) * | 2003-07-09 | 2005-01-13 | Fuji Photo Film Co., Ltd. | Thermal printer adapted to shorten a fixing time |
US20060050133A1 (en) * | 2004-09-08 | 2006-03-09 | Fuji Photo Film Co., Ltd. | Luminous device and optical fixing device |
Families Citing this family (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2005199476A (en) * | 2004-01-13 | 2005-07-28 | Fuji Photo Film Co Ltd | Illuminating device |
JP4649935B2 (en) * | 2004-02-02 | 2011-03-16 | コニカミノルタホールディングス株式会社 | Inkjet printer |
US7661807B2 (en) * | 2004-07-21 | 2010-02-16 | Seiko Epson Corporation | Ultraviolet rays emitter |
CN104298078A (en) * | 2009-05-14 | 2015-01-21 | 4233999加拿大股份有限公司 | System for and method of providing high resolution images using monolithic arrays of light emitting diodes |
DE102016216627A1 (en) | 2016-09-02 | 2018-03-08 | Krones Ag | Curing station and method for curing ink of direct printing on containers |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5119132A (en) * | 1990-10-24 | 1992-06-02 | Xerox Corporation | Densitometer and circuitry with improved measuring capabilities of marking particle density on a photoreceptor |
US5229870A (en) * | 1990-02-15 | 1993-07-20 | Sharp Kabushiki Kaisha | Light emitting device capable of readily controlling total quantity of light under a balanced light emitting state of light emitting elements |
US5986682A (en) * | 1996-02-29 | 1999-11-16 | Mitsubishi Denki Kabushiki Kaisha | Recording apparatus and recording method |
JP2001171157A (en) * | 1999-12-16 | 2001-06-26 | Fuji Photo Film Co Ltd | Color thermal printer |
US6583791B2 (en) * | 1998-08-20 | 2003-06-24 | Hybrid Electronics Australia Pty Ltd. | Method and apparatus for color-correction of display modules/LEDs of red, green and blue color-correction combinations |
-
2002
- 2002-07-17 JP JP2002208675A patent/JP2003285456A/en active Pending
-
2003
- 2003-01-24 US US10/350,133 patent/US6870558B2/en not_active Expired - Fee Related
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5229870A (en) * | 1990-02-15 | 1993-07-20 | Sharp Kabushiki Kaisha | Light emitting device capable of readily controlling total quantity of light under a balanced light emitting state of light emitting elements |
US5119132A (en) * | 1990-10-24 | 1992-06-02 | Xerox Corporation | Densitometer and circuitry with improved measuring capabilities of marking particle density on a photoreceptor |
US5986682A (en) * | 1996-02-29 | 1999-11-16 | Mitsubishi Denki Kabushiki Kaisha | Recording apparatus and recording method |
US6583791B2 (en) * | 1998-08-20 | 2003-06-24 | Hybrid Electronics Australia Pty Ltd. | Method and apparatus for color-correction of display modules/LEDs of red, green and blue color-correction combinations |
JP2001171157A (en) * | 1999-12-16 | 2001-06-26 | Fuji Photo Film Co Ltd | Color thermal printer |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20050007439A1 (en) * | 2003-07-09 | 2005-01-13 | Fuji Photo Film Co., Ltd. | Thermal printer adapted to shorten a fixing time |
US20060050133A1 (en) * | 2004-09-08 | 2006-03-09 | Fuji Photo Film Co., Ltd. | Luminous device and optical fixing device |
Also Published As
Publication number | Publication date |
---|---|
JP2003285456A (en) | 2003-10-07 |
US20030142195A1 (en) | 2003-07-31 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US20050151831A1 (en) | Light emitting device | |
EP1564709A2 (en) | A method for measuring forward voltage drop | |
EP0529540B1 (en) | Electronic drive circuit for multi-laser thermal printer | |
KR100854192B1 (en) | Flat lighting source, luminance correcting circuit, luminance correcting method and liquid crystal display | |
JP4463024B2 (en) | Light emitting device | |
JP4402336B2 (en) | Planar light source device and liquid crystal display device using the same | |
US7969430B2 (en) | Voltage controlled backlight driver | |
US20060050133A1 (en) | Luminous device and optical fixing device | |
JP7143185B2 (en) | image forming device | |
US11800610B2 (en) | Method of driving an emitter array | |
US20090273930A1 (en) | Light-Emitting Diode Module, Method for Producing a Light-Emitting Diode Module and Optical Projection Apparatus | |
US6870558B2 (en) | Optical fixing unit, illuminance correcting method for the same, and thermal printer | |
US6642492B2 (en) | Calibration apparatus for light emitting elements in an optical printer | |
JP4970514B2 (en) | Planar light source device and liquid crystal display device using the same | |
KR19990044363A (en) | Exposure apparatus, exposure method and printing apparatus | |
JP4274536B2 (en) | Semiconductor light emitting device | |
JP4970515B2 (en) | Planar light source device and liquid crystal display device using the same | |
JP2005109025A (en) | Circuit for driving light-emitting device | |
US20100225730A1 (en) | Exposure device, image forming apparatus and computer-readable medium | |
JP2002002045A (en) | Color sensor and color detecting method for ink ribbon | |
JP2006245308A (en) | Light source apparatus | |
US6788323B2 (en) | Printer | |
JP2006245307A (en) | Light source apparatus | |
JP2006325024A (en) | Contact image sensor | |
US7253828B2 (en) | Exposure-energy-density and dynamic effect based uniformity correction for LED printheads |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: FUJI PHOTO FILM CO., LTD., JAPAN Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:KATSUMA, NOBUO;MACHIDA, AKIHIKO;REEL/FRAME:013709/0385 Effective date: 20030108 |
|
AS | Assignment |
Owner name: FUJIFILM CORPORATION, JAPAN Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:FUJIFILM HOLDINGS CORPORATION (FORMERLY FUJI PHOTO FILM CO., LTD.);REEL/FRAME:018904/0001 Effective date: 20070130 Owner name: FUJIFILM CORPORATION,JAPAN Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:FUJIFILM HOLDINGS CORPORATION (FORMERLY FUJI PHOTO FILM CO., LTD.);REEL/FRAME:018904/0001 Effective date: 20070130 |
|
FPAY | Fee payment |
Year of fee payment: 4 |
|
FEPP | Fee payment procedure |
Free format text: PAYOR NUMBER ASSIGNED (ORIGINAL EVENT CODE: ASPN); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY |
|
REMI | Maintenance fee reminder mailed | ||
LAPS | Lapse for failure to pay maintenance fees | ||
STCH | Information on status: patent discontinuation |
Free format text: PATENT EXPIRED DUE TO NONPAYMENT OF MAINTENANCE FEES UNDER 37 CFR 1.362 |
|
FP | Lapsed due to failure to pay maintenance fee |
Effective date: 20130322 |